A pressure and flow adjustable dimethyl ether supply system

Abstract

The purpose of this invention is to provide a dimethyl ether (DME) supply system with adjustable pressure and flow rate, belonging to the field of engine technology. It includes a two-phase DME storage tank, a pressure stabilizing vessel, a variable booster device, and a high-pressure common rail. The gas outlet of the two-phase DME storage tank is connected to a DME gas supply pipeline. A DME injection valve is installed at the end of the DME gas supply pipeline. The liquid outlet of the two-phase DME storage tank is connected to a low-pressure DME delivery pipeline, which is connected to the pressure stabilizing vessel. The variable booster device is connected to both the pressure stabilizing vessel and the high-pressure common rail. The high-pressure common rail is connected to an electronically controlled DME injector. This invention enables variable adjustment of the system supply flow rate; the pressure inside the pressure stabilizing vessel is adjusted by a control module, and linear control of the supply pressure is achieved using the fixed area ratio of a dual-piston caliper. Through the coupled control method of in-cylinder direct injection and intake manifold injection, the total DME supply is effectively increased, meeting the supply requirements of the internal combustion engine across all operating conditions.

Description

Technical Field

[0001] The present invention relates to an engine, specifically a fuel supply system. Background Technology

[0002] Dimethyl ether (DME), as a clean alternative fuel, boasts advantages such as high cetane number and low emissions, showing promising prospects in internal combustion engine applications. However, the low energy density, low viscosity, and high saturated vapor pressure of DME lead to problems in fuel supply systems, including high demand flow rates, easy leakage, and susceptibility to vaporization, limiting the performance optimization of internal combustion engines across the entire operating range. Existing technologies typically employ multi-stage pressurization and complex sealing structures to address the delivery and pressurization issues of DME, which not only increases system complexity and cost but also reduces the flexibility of supply system adjustments. Summary of the Invention

[0003] The purpose of this invention is to provide a dimethyl ether supply system with adjustable pressure and flow rate that can solve the problems of large dimethyl ether demand, difficulty in pressurization, easy leakage, and difficulty in adjusting supply parameters.

[0004] The objective of this invention is achieved as follows: This invention discloses a dimethyl ether (DME) supply system with adjustable pressure and flow rate, characterized by comprising a two-phase DME storage tank, a pressure stabilizing vessel, a variable pressurization device, and a high-pressure common rail. The gas outlet of the two-phase DME storage tank is connected to a DME gas supply pipeline. A DME injection valve is installed at the end of the DME gas supply pipeline. The liquid outlet of the two-phase DME storage tank is connected to a low-pressure DME delivery pipeline. The low-pressure DME delivery pipeline is connected to the pressure stabilizing vessel. The variable pressurization device is connected to both the pressure stabilizing vessel and the high-pressure common rail. The high-pressure common rail is connected to an electronically controlled DME injector.

[0005] The present invention may also include: 1. The variable booster device includes a housing and a dual-head booster piston. The dual-head booster piston is installed inside the housing and includes a large-end piston and a small-end piston connected together. The large-end piston and the housing form a power chamber, and the small-end piston and the housing form a booster chamber. The power chamber and the pressure stabilizing container are respectively connected through a power chamber supply pipeline and a power chamber return pipeline. The booster chamber is respectively connected through a booster chamber supply pipeline and a booster chamber return pipeline. The booster chamber is connected to the high-pressure common rail through a high-pressure dimethyl ether supply pipeline.

[0006] 2. The high-pressure common rail is connected to the pressure stabilizing container through the high-pressure return oil line, and a pressure relief valve is installed at the inlet of the high-pressure return oil line.

[0007] 3. A pressure reducing valve is installed on the high-pressure return oil pipeline.

[0008] 4. A power dimethyl ether control valve is installed on the power chamber supply pipeline, a power chamber return oil control valve is installed on the power chamber return oil pipeline, a booster dimethyl ether control valve is installed on the booster chamber supply pipeline, and a booster chamber return oil control valve is installed on the booster chamber return oil pipeline. By controlling the opening and closing sequence and opening degree of the power dimethyl ether control valve, the power chamber return oil control valve, the booster dimethyl ether control valve, and the booster chamber return oil control valve, the booster frequency of the double-head booster piston stroke is changed, thereby realizing the variable adjustment of the supply flow rate.

[0009] 5. A second check valve is installed on the return oil line of the power chamber, and a third check valve is installed on the return oil line of the booster chamber.

[0010] 6. A fourth check valve is installed on the high-pressure dimethyl ether supply pipeline.

[0011] 7. A diaphragm pump and a first check valve are installed sequentially on the low-pressure dimethyl ether delivery pipeline.

[0012] 8. The dimethyl ether gas supply pipeline is equipped with a dimethyl ether gas control valve and a dimethyl ether gas delivery pump.

[0013] 9. The pressure stabilizing container is equipped with an integrated cooling circuit, a safety valve, a pressure stabilizing valve, and an unloading valve.

[0014] The advantages of this invention are: 1. Through the control module, the opening and closing sequence and opening degree of the power dimethyl ether control valve, power chamber return valve, booster dimethyl ether control valve and booster chamber return valve in the variable booster device are controlled in a coordinated manner. This can quickly change the stroke and boosting times of the dual-head booster piston per unit time, thereby realizing the variable regulation and rapid response of the high-pressure dimethyl ether supply flow.

[0015] 2. By adjusting the pressure of dimethyl ether in the pressure stabilizing container and utilizing the fixed area ratio of the double-headed pressure boosting piston, the output pressure of high-pressure dimethyl ether can be linearly set, thereby achieving variable control and rapid response of the high-pressure dimethyl ether supply pressure.

[0016] 3. The diaphragm pump initially pressurizes dimethyl ether to a subcooled state, increasing its mass flow rate and preventing cavitation and gas lock phenomena in the pipeline. During the process of pressurizing dimethyl ether with dimethyl ether in the variable pressurization device, the power chamber can recover the dimethyl ether leaked in the pressurization chamber.

[0017] 4. When the internal combustion engine is under medium or low load conditions, a flexible and variable supply strategy can be achieved by using high-pressure liquid-phase dimethyl ether direct injection in the cylinder alone; when the internal combustion engine is under high load conditions, by coupling and controlling the high-pressure liquid-phase dimethyl ether direct injection in the cylinder and the low-pressure gas-phase dimethyl ether intake port injection, the total supply of dimethyl ether can be effectively increased to meet the demand of the internal combustion engine for dimethyl ether under high load conditions. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention.

[0019] Figure reference numerals: 1: Dimethyl ether two-phase storage tank; 2: Filter; 3: Diaphragm pump; 4: Low-pressure dimethyl ether delivery pipeline; 5: One-way valve 1; 6: Pressure stabilizing vessel; 7: Power chamber supply pipeline; 8: Power dimethyl ether control valve; 9: Variable pressure boosting device; 10: Large end piston; 11: Pressure boosting chamber supply pipeline; 12: Small end piston; 13: Pressure boosting dimethyl ether control valve; 14: Pressure boosting chamber return oil control valve; 15: Pressure boosting chamber return oil pipeline; 16: ... 17: Power chamber return oil control valve; 18: Power chamber return oil line; 19: Check valve 2; 20: Check valve 3; 21: Pressure reducing valve; 22: Check valve 4; 23: High-pressure dimethyl ether supply line; 24: Electronically controlled dimethyl ether injector; 25: High-pressure common rail; 26: Pressure relief valve; 27: High-pressure return oil line; 28: Dimethyl ether gas control valve; 29: Dimethyl ether gas supply line; 30: Dimethyl ether gas delivery pump; 41: Dimethyl ether gas injection valve Detailed Implementation

[0020] The invention will now be described in more detail with reference to the accompanying drawings: Combination Figure 1 The present invention includes a dimethyl ether two-phase storage tank 1, a diaphragm pump 3, a pressure stabilizing container 6, a power dimethyl ether control valve 8, a variable pressurization device 9, a pressurized dimethyl ether control valve 13, a pressurization chamber return oil control valve 14, a power chamber return oil control valve 16, an electronically controlled dimethyl ether injector 23, a high-pressure common rail pipe 24, a dimethyl ether gas control valve 27, a dimethyl ether gas delivery pump 29, a dimethyl ether gas injection valve 30, a system status monitoring module, and a control module.

[0021] Dimethyl ether two-phase storage tank 1 is used to store dimethyl ether in a gas-liquid coexistence state. The dimethyl ether two-phase storage tank is equipped with a dimethyl ether inlet, a safety valve, a dimethyl ether liquid outlet, and a dimethyl ether gas outlet. The dimethyl ether liquid outlet is connected to the filter 2, and the dimethyl ether gas outlet is connected to the dimethyl ether gas delivery pipeline 28 via the dimethyl ether gas control valve 27.

[0022] Filter 2 is installed at the inlet of diaphragm pump 3 to filter solid impurities in dimethyl ether liquid. Diaphragm pump 3 is used to pressurize the saturated liquid dimethyl ether in storage tank 1 into subcooled dimethyl ether. The outlet of diaphragm pump 3 is connected to low-pressure dimethyl ether delivery pipeline 4. The pressurized dimethyl ether is delivered to pressure stabilizing container 6 through low-pressure dimethyl ether delivery pipeline 4. Check valve 5 is installed between low-pressure dimethyl ether delivery pipeline 4 and pressure stabilizing container 6 to prevent backflow of dimethyl ether in low-pressure dimethyl ether delivery pipeline 4.

[0023] The pressure stabilizing vessel 6 has multiple dimethyl ether inlets and outlets, which are respectively connected to the low-pressure dimethyl ether supply line 4, the power chamber supply line 7, the booster chamber supply line 11, the booster chamber return line 15, the power chamber return line 17, and the high-pressure return line 26. The pressure stabilizing vessel 6 has an integrated cooling circuit inside to control the temperature of the dimethyl ether inside the vessel, and a safety valve is installed on the top for overpressure protection. In addition, the pressure stabilizing vessel 6 includes a pressure regulating valve and an unloading valve to regulate its internal pressure.

[0024] The power chamber supply line 7 connects the pressure stabilizing container 6 to the inlet of the power chamber of the variable pressure boosting device 9, and is used to deliver dimethyl ether to the power chamber. The power dimethyl ether control valve 8 is installed in the line 7 to control the flow rate of dimethyl ether entering the power chamber.

[0025] The variable pressurization device 9 includes a dual-head pressurization piston, a power chamber, and a pressurization chamber. The dual-head pressurization piston includes a large-end piston 10 and a small-end piston 12. When the dimethyl ether in the power chamber pushes the large-end piston 10, the small-end piston 12 simultaneously compresses the dimethyl ether in the pressurization chamber. When the dual-head pressurization piston reaches force balance, the pressure ratio of the dimethyl ether in the power chamber and the pressurization chamber is equal to the area ratio of the large-end piston 10 and the small-end piston 12, thereby realizing the secondary pressurization of the dimethyl ether and generating high-pressure dimethyl ether.

[0026] High-pressure dimethyl ether in the boost chamber of the variable booster 9 is discharged through a one-way valve 21, and then transported to the high-pressure common rail 24 via the high-pressure dimethyl ether supply line 22. The electronically controlled dimethyl ether injector 23 is connected to the common rail 24 and is used to inject high-pressure dimethyl ether into the cylinder of the internal combustion engine.

[0027] The return oil lines of the variable booster device 9 include a power chamber return oil line 17 and a booster chamber return oil line 15, each equipped with a one-way valve 18 and a one-way valve 19, respectively, so that the return oil flows unidirectionally into the pressure stabilizing container 6. A pressure relief valve 25 is installed on the high-pressure common rail 24, and overpressure fuel flows back to the pressure stabilizing container 6 through the high-pressure return oil line 26 and the pressure reducing valve 20, which can realize energy recovery and reduce system power consumption.

[0028] The present invention also includes a monitoring module for monitoring the internal combustion engine speed, the pressure in the high-pressure common rail 24, the pressure in the pressure stabilizing container 6, the speed of the diaphragm pump 3, and the speed of the dimethyl ether gas delivery pump 29.

[0029] The present invention also includes a control module for regulating the opening and closing sequence and opening degree of the power dimethyl ether control valve 8, the booster dimethyl ether control valve 13, the power chamber return oil control valve 16, and the booster chamber return oil control valve 14; the control module can regulate the pressure in the pressure stabilizing container 6, the speed of the diaphragm pump 3, and the speed of the dimethyl ether gas delivery pump 29; the control module can also regulate the opening and closing sequence of the electronically controlled dimethyl ether injector 23, the dimethyl ether gas control valve 27, and the dimethyl ether gas injection valve 30.

[0030] The variable adjustment of system supply pressure and flow rate is achieved through the following methods: Pressure regulation: By controlling the pressure regulating device in the pressure stabilizing container 6 and the rotation speed of the diaphragm pump 3, the pressure inside the pressure stabilizing container 6 and the oil inlet pressure of the power chamber and booster chamber of the variable booster device 9 are adjusted, thereby realizing the adjustable output pressure of the system.

[0031] Flow regulation: By controlling the opening and closing sequence and opening degree of the power dimethyl ether control valve 8, the booster dimethyl ether control valve 13, the booster chamber return oil control valve 14 and the power chamber return oil control valve 16, the amount of dimethyl ether filling in the power chamber and the booster chamber of the variable booster device 9 is controlled, and the stroke and boosting times of the dual-head booster piston are changed, thereby achieving adjustable system flow.

[0032] The specific structural form of the variable booster device 9, the area ratio of the dual-head booster piston, the installation position of the control valve, the opening and closing sequence and frequency can all be adjusted according to actual application requirements.

Claims

1. A dimethyl ether supply system with adjustable pressure and flow rate, characterized in that: The system includes a two-phase dimethyl ether storage tank, a pressure stabilizing vessel, a variable pressurization device, and a high-pressure common rail. The gas outlet of the two-phase dimethyl ether storage tank is connected to a dimethyl ether gas supply pipeline. A dimethyl ether injection valve is installed at the end of the dimethyl ether gas supply pipeline. The liquid outlet of the two-phase dimethyl ether storage tank is connected to a low-pressure dimethyl ether delivery pipeline. The low-pressure dimethyl ether delivery pipeline is connected to the pressure stabilizing vessel. The variable pressurization device is connected to both the pressure stabilizing vessel and the high-pressure common rail. The high-pressure common rail is connected to an electronically controlled dimethyl ether injector.

2. The dimethyl ether supply system with adjustable pressure and flow rate according to claim 1, characterized in that: The variable booster device includes a housing and a dual-head booster piston. The dual-head booster piston is installed inside the housing and includes a large-end piston and a small-end piston connected together. The large-end piston and the housing form a power chamber, and the small-end piston and the housing form a booster chamber. The power chamber and the pressure stabilizing container are respectively connected through a power chamber supply pipeline and a power chamber return pipeline. The booster chamber is respectively connected through a booster chamber supply pipeline and a booster chamber return pipeline. The booster chamber is connected to the high-pressure common rail through a high-pressure dimethyl ether supply pipeline.

3. The dimethyl ether supply system with adjustable pressure and flow rate according to claim 1, characterized in that: The high-pressure common rail is connected to the pressure stabilizing vessel via a high-pressure return oil line, and a pressure relief valve is installed at the inlet of the high-pressure return oil line.

4. The dimethyl ether supply system with adjustable pressure and flow rate according to claim 3, characterized in that: A pressure reducing valve is installed on the high-pressure return oil line.

5. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 2, characterized in that: A power dimethyl ether control valve is installed on the power chamber supply line, a power chamber return oil control valve is installed on the power chamber return oil line, a booster dimethyl ether control valve is installed on the booster chamber supply line, and a booster chamber return oil control valve is installed on the booster chamber return oil line. By controlling the opening and closing sequence and opening degree of the power dimethyl ether control valve, the power chamber return oil control valve, the booster dimethyl ether control valve, and the booster chamber return oil control valve, the boosting frequency of the double-head booster piston stroke is changed, thereby achieving variable adjustment of the supply flow rate.

6. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 2, characterized in that: A second check valve is installed on the return oil line of the power chamber, and a third check valve is installed on the return oil line of the booster chamber.

7. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 2, characterized in that: A fourth check valve is installed on the high-pressure dimethyl ether supply pipeline.

8. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 1, characterized in that: A diaphragm pump and a first check valve are sequentially installed on the low-pressure dimethyl ether delivery pipeline.

9. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 1, characterized in that: The dimethyl ether gas supply pipeline is equipped with a dimethyl ether gas control valve and a dimethyl ether gas delivery pump.

10. A dimethyl ether supply system with adjustable pressure and flow rate according to claim 1, characterized in that: The pressure stabilizing vessel is equipped with an integrated cooling circuit, a safety valve, a pressure stabilizing valve, and an unloading valve.

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